In recent years, a variety of puncture sealing agents are available on the market. They mainly contain a colloidal dispersion system polymer in an aqueous medium and are known as latexes. In other words they use, for example, a polyethylene-butadiene latex, a polyvinyl acetate latex, an acrylic copolymer latex, a nitrile latex, an acrylonitrile-butadiene latex, a polychloroprene latex. In addition, also known is a puncture sealing agent containing, as the carrier medium, tetrachloroethylene rather than water.
In order to introduce such a puncture sealing agent into the inside of a tire, and to pump up the tire to a pressure at which it can be used, an apparatus having a pressure-tight container for the puncture sealing agent that contains a liquefied gas as a pressure source, such as a spray can, has been conventionally used. In addition, as the liquefied gas, a propane-butane gas mixture is mainly used, however, fluorochlorohydrocarbons are also used in rare cases. One end of a hose is connected to the spray can with an outlet valve, and a screw adapter for use with a tire valve is attached to the other end of the hose.
When a tire puncture occurs, the puncture sealing agent is squirted out from the spray can into the interior of the tire through the tire valve, and with the propellant gas, the tire is reinflated to a specific pressure level that varies depending upon the amount of gas leakage. At this time, the puncture sealing agent is distributed in the interior of the tire to seal off the damaged portion, while running for a distance of a few km, depending upon the degree of damage to the tire.
In another apparatus, the puncture sealing agent is placed in a compressible flask that is connected, through an adapter, to the tire valve from which a valve insertion has been previously removed. The puncture sealing agent is squirted out into the interior of the tire by compressing the flask. After the valve insertion is inserted, and the tire is reinflated to a specific internal pressure with the aid of carbon dioxide cartridges.
By the way, the puncture sealing agents that have been conventionally used are not fully satisfactory. They can be mechanically removed relatively quickly, and the speed at which the puncture hole is blocked up is slow, thus it takes a considerably long period of time to carry out the preliminary running, for completing the sealing, before real running can be made.
Conventional apparatuses that introduce the puncture sealing agent into the interior of the tire to pump up the tire are also problematic. The temperature at which a spray can, containing a propane-butane gas mixture as the propellant gas, can be used depends upon the mixing ratio. However, unless the temperature falls down to approximately 0° C., the spray can cannot be satisfactorily used. Further, a propane-butane gas mixture is combustible and explosive. Furthermore, a fluorochlorohydrocarbon can have an ill effect on the environment. In addition, all the well-known propellant gases are available only in a limited quantity in the event a puncture occurs.
As a puncture sealing agent and a tire pumping-up apparatus that can solve the above-mentioned problems, for example, the patent literature 1 discloses a puncture sealing agent that includes a rubber latex containing natural rubber latex alone, and has a resin-based adhesive agent that is compatible with this natural rubber latex, and a sealing/pumping-up apparatus that uses this puncture sealing agent.
However, about the above-mentioned conventional puncture sealing agents, it cannot be said that they are sufficient in puncture sealing properties, such as puncture sealing speed, and storage stability in the sense of freedom from coagulation even during long-term storage, and thus there is still room for improvement.
Patent literature 1: Japanese Patent Application No. H09-118779